Electromagnet



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S. M. LUCAS. ELECTROMAGNET.

APPLICATION FILED DEC. 16, 1920. v

Patented June 27, 1922.

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INVENTOR:

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Ot' K' M,

v/.CA TTORNEY.

s.- M. Luc-As.

ELECTROMAGNET. APPLICATION FILED DEC. 16, 1920.

PtentedJune 27, 1922.

4 SHEETS-SHEET 2.

INVENTOR.'

W, Q.' z' M,

I S. M. LUCAS.

ELECTROMAGNET.

APPLxcATloN FILED 1350.16, 1920.

Patented June 27,1922.

4 SHEETS-SHEET 3.

MATTORNEY.

s. M.VLUCAS. ELECTRONIAGNET.

APPLICATION. FILED DEC. 16. 1920.

1,42 1,269, Patent-emp@ 27, 1922.

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IN VENTR.

:BY @nuw- HJ., l A TTORNEY.

UNITED' STATES SAMUEL M. LUCAS, PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 THE UNION SWITCH & SIGNAL COMPANY, 0F SW TION OF PENNSYLVANIA.

Pa'lie-mv OFFICE.

ISSVALE, PEN'NSYLV'ANIA, A CORPORA ELECTROMAGNET.

T o all whom t may concern;

Be it known that I, SAMUEL M. LUCAS, a citizen of the United States, residing at Pittsburgh, in thefcounty of Allegheny and AState of Pennsylvania, have invented certain new and useful Improvements in Electromagnets, of which the following is-a specification. v

My invention relates to electromagnets, and particularly to magnets of the type com,-

prising a neutral armature responsive to the presence and absence of current, anda polarized armature lresponsive to the polarity of the current supplied to the magnet,

One object of my invention is the provision of a magnet of this character the neutral armature of which is not released when the polarityof the current supplied to the relay is.

reversed.

Magnets embodying my invent-ion are particularly well adapted for use in electrical relays, and in the present application they are illustrated in connection with devices of this nature, with the understanding that they are not limitedtothis specific adaptation but are capable of general application.

I will describe several relays in which are incorporated various forms of magnets embodying my invention," and will then point out the novel features thereof in claims.

I In the accompanying drawings, Fig. 1 is a. view, partly in front elevation and partly diagrammatic, showing a relay having one form of eleetromagnet embodying my invention. Fig. 2 is a sectional view on the 'line II-II of Fig. l'with the winding omitted.

Fig. 3 is a View similar to Fig. lbut showing a modified form ofl electromagnet embodying my invention. F ig..4 is a sectional View on the line IV-IV of Fig. 3 with the winding omitted. Fig. 5 is a view similar toFig. 1 but'showing another modified form of electromagnet embodying'my invention. Fig. 6

is a sectional'view on the line VI-VI ofv Fig. 5 with the winding omitted. Figa-'7 is a view showing in front' elevation a fourth.

form of electromagnet embodying my in- -vention. Fi 8 is a sectional view on the line VIIIe II of Fig. 7, and Fig. 9 is a top plan view of the magnet shown in Fig. 7.

Similar reference characters refer to simi-A 12b- 13 and -12-'-16 are c osed, and when lar parts in each of the vseveral views.

Referring rst to Fig. 1,the electromagnet in the form here shown includes, a U-shaped or the other.

Specification ofLetters Patent. Patented J une 27, 1922. Application filed December 16, 1920.' Serial No. 431,078.

soft iron core A, having a back strap 11 and two legs each of which comprises two parallel sections 2 and 2a. Each leg section 221 encased in a tube or sleeve 3 of non-magnetizable electro-conductive material such as copper, but the leg sections 2 are not provided with such tubes. The magnet is pro-v `from the poles of the magnet, that is, the

free ends of the core sections 2 and 2a. lt will be seen, therefore, that substantially all of the magnetic fiux in the core A passes through the neutral armature, so that this armature is closed against the poles of the core when winding-4 is `supplied with cur- A rent, and falls away from the pole cores or opens,by`gravity, when the supply of current to the winding ceases. As here. shown, oneA or more Contact iingers 6 are attached to armature 5 by studs 8 of insulating material, and each of these lingers coacts with a iXed contact member 7 in such manner that the contact is closed when the armature is closed, and-open when-the armature is open.

The reference character 10designates a polarizing member such as a permanent magnet, one end of which is attached to the back strap 11 of the core A midway between the two core legs, and the free end of which is bifurcated to permit a polarized armature 9 to be pivotally mounted therein at 9, The polarized armature may beV L- `shaped as shown in the drawing, and is arranged to swing between two extreme posi- A tions wherein its arms are substantially in engagement with section 2 of one core leg Armature 9 carries one or more contact fingers, such as 12 and 12", which fingers co-act with fixed Contact members 131,' 14, 15 and 16. Whenthe armature is in the ,extreme left'hand osition, contacts the armature is swung to its extreme right handV position, contacts lZ-l -and 12-14il s copper tube 3",

will become closed. It will, of course, be understood that when current of one polarity is supplied to winding 4, armature 9 will be swung to the left, and that when current of the other polarity is supplied to this winding the armature will be swung to the right.

The purpose of the tubes 3 is to delay the reversal of flux in the core leg sections 2a when the polarity of the current supplied to the winding 4 is reversed. The result of these tubes is that during reversal of polarity theflux in core sections 2 reverses before the flux in section 21, so that at all times during reversal of polarity some flux is passing into and out of the neutral armature 5. It follows that this armature is notA released durig/ reversal of polarity of the current in Winding 4.

Referring now to Figs. 3 and 4, the

structure is substantiallythe same as that shown in Figs. 1 and 2, except that each leg of the core, which is here designated comprises three parallel sections 2,' 2l and 2b., Section 2 of each leg is provided with a copper tube 3", while section'2b of each leg is provided with a copper tube 3b. The tube 3" is yof larger cross ,sectional area, and, consequently, of lower electrical resistance, than the tube 3*, so that during reversal of polarity the flux inleg section 2b does not reverse until after the flux in section 2 has reversed.- lThat is, the 'tubeA 3 delays the decay of flux inleg section 2 while the flux in section2 is reversing, and the tube 3* delays the decay tion 2b while the fluxin. section 2a -is reversing. It follows that lthe pull on the neutra armature .5 does not pass through zero, and that, consequently, the' neutral armature does not wlndlng 4.

With structurevshown in Fig. 3, the theoretical maximum attainable ull on armature 5 during reversal of pollarity dro to two-thirds of the normal-pull exerte on this armature by the magnet cores.v In this respect the structure preferable to that shown in Fig. 1, wherein the theoretical maximum attainable pull on armature 5 during reversal of polarity drops" to one-half of thereon.'

Referring now to Figs. 5 and 6, the structure shown therein is similar to that shown the pull normally exerted in Figs. 3 and 4, with the exception of the I arrangement of the copper tubes. In this instance the core leg 2 1s surrounded b a and the two legs 2* an 2b are surrounded During reversal rent supplied to the relay windings, the tube 3c delays the decay of flux in sections 2*: and 2 while the flux in section 2 is reof flux insecopen during -reversal of the. polarity of the current supplied. to-

by a second copper tube.4 3. of the polarityof the cur' versing` whereas the Vtube 3b delays the de- Cay of flux in section 2b while the flux in section 2l is reversing. The net result is substantially the same as that of the device shown in Figs. 3 and 4.

Referring now to the structure shown in Figs. 7, 8, and 9, each leg of the core, A comprises a cylindrical inner section 2 surrounded by a copper sleeve 3 which, in turn, is surrounded by an outer sleeve 2x1 of soft iron constituting the second section of the core leg. finding 4 surrounds the outer section 2E. The lpermanent magnet l0 in this instance projects downwardly from an offset portion 11a of the back-strap, and the polarized armature 9 is pivotally mounted at the lower end of such magnet to swing ona vertical axis, one end or the otherl o the armature being attracted towards the corresponding outer leg section 2a according as the winding 4 is supplied with current of one polarity or the other.

The operation of this form of magnet will be readily understood. When the polarity of the current in winding 4 is reversed, the flux in each core section 2a reverses before the flux in section 2, so that some flux is passing in or out of armature 5 at all times duringr such reversal and so this armature remains closed.

Relays incorporating electroma ets embodying my invention arey particu arly well adapted for use in connection with railway signaling apparatus, although they are not limited to this particular application. Although I' have herein shown and de- -scribed only four forms of electromagnets embodying my invention, it is understood that'various changes and modifications may be made-therein within the scope of the appended claims without departingfrom .the spirit and scope of my invention.

Having thus described my invention, what I claim is': l. An electromagnet comprising a neutral armature and a polarized armature, a wind 111g for creating magnetic flux to control both of said armatures, and means for delaying the reversal of part of the flux in the neutral armature when the clarity of the current supplied to said win lng is reversed. 2. An electroma et comprislng a neutral armature and a'po arized armature, a wind-V ing, two paths for magnetic fiux created by said winding, the" flux in one path controlling the` polarized armature and the fluxes in both paths controlling theneutra'l armature, and means for delaying the reversal ofthe flux which does not control the polarized armature when the polarity of the current-supplied to said windlng is reversed. i 3. An electromagnet comprising aneutral armature and a polarized armature, a;

trol. said armatures, and means for delaying the change of intensity of part of the lux employed for controlling said neutral armature when 'the intensity of the current supplied to said winding is'varied. I

4. An electromagnet comprising a Winding, tWo paths for the Inagnetic flux produced by current in said winding, means for 'delaying the reversal of the flux in one path until after the reversal has occurred in the other path when the polarity of the current supplied to said Winding is reversed, a neutral armature controlled by theflux in both paths, and a polarized armature controlled by the flux in one path. A

5. An electromagnet comprising a Winding, two paths for the magnetic flux produced by current in said Winding, means for delaying the reversal of the flux in one path until after the reversal has occurred in the other path when the polarity of the current' supplied to said windin is reversed, a polarized armature contro led by the flux in the secondl path, and a neutral armature controlled by the fluxes in both paths.`

6. An electromagnet comprising a core having two sections in multiple, a .Winding for creating magnetic flux in said core, a

tube of non-magnetizable electro-conductive material surrounding one of said sections, a polarized armature controlled by the flux in one section, and a neutral armature con- .trolled by the fluxes in both sections.

7. An electromagnet comprising al Winding, a plurality of paths for the magnetic flux produced by current in said Winding, means for causing reversal of the iux successively in the several paths when the polarity of the current supplied to said Winding is reversed, andneutral and polarized armatures controlled by the fluxes in said paths.

v8. An electromagnet comprising a Winding, a plurality of. paths for the magnetic flux' produced by current in said winding, means for causing reversal of the flux successively in the several paths when the polarit-y-of the current supplied to said winding is reversed, a neutral armature controlled for causing reversal of flux successively in the several paths when the polarity of the current supplied to said Winding is reversed.

v10. Anelectromagnet comprising a neutral and a polarized armature, a winding forl creating magnet flux 'to control said armatures, a core for said Winding having a plurality of sections in multiple, and tubes of non magnetizable electro -conductive material surroundingcertain of said sections and arranged to cause successive reversals of flux in the several sections upon reversal of polarity of the current supplied to said winding. v

11. An electromagnet comprising a U- shaped core each leg of which comprises at least two parallel sections,v a winding for creating magnetic flux in said core, means associated with each leg of said core for delaying the reversal of flux in one section thereon until the fiux in the other section has reversed upon reversal of the polarity of the current supplied to said Winding, a neutral armature controlled by the fluxes in both sections of each leg, and a polarized armature controlled by theilux in one section of each leg.

In testimony whereof I, affix my signature. l

' SAMUEL M. LUCAS. 

